1. Field of the Invention
The present invention relates generally to chip antennas and, more particularly, to chip antennas used in mobile communications and local area networks (LAN).
2. Description of the Related Art
FIG. 3 illustrates a conventional monopole antenna 50. This antenna 50 has one conductor 51 projecting into the air substantially perpendicularly from a ground surface 52 (having a relative dielectric constant .epsilon. of 1 and a relative magnetic permeability .mu. of 1). The conductor 51 is connected at its one end 53 to a power supply V and is opened at the other end 54.
In a linear-type antenna represented by the above type of monopole antenna 50, a large conductor is required because of the operation of the antenna being in the air. In the monopole antenna 50, for example, if a wavelength in a vacuum is .lambda.o, a conductor 51 having a wavelength of .lambda.o/4 is needed; in a low-frequency band of 1 GHz or lower, the length of the monopole antenna 50 is 7.5 cm or longer. Thus, this type of antenna cannot be used in applications where a miniature antenna is required, such as in low-frequency mobile communications.